Means for stabilizing wellbores

ABSTRACT

Disclosed herein is an expandable casing comprised of inside and outside axial sections of casings which fasten to form a sealed casing joint capable of withstanding pressure and formation loads as the casing is expanded and locked into position. The expandable casing stabilizes wellbores, preventing deformation, fracturing or fluid communication between fluids conducted within the wellbore and formations isolated through use of the casing. The casing sections are attached to an inflatable bladder element which affords placement through smaller diameter wellbores and orderly expansion of the sections in the wellbore adjacent to the formation to be stabilized or protected.

United States Patent Land 1 51 July 17, 1973 MEANS FOR STABILIZING WELLBORES [75] Inventor: Karl M. Land, Tulsa, Okla. pnmary Examlf'er james Leppmk Att0rney-J. Richard Geaman [73] Assignee: Cities Service Oil Company, Tulsa,

Okla. [57] ABSTRACT [22] F1led: June 18, 1971 l d h d d f Disc ose erein is an expan able casing comprise 0 Appl 154540 inside and outside axial'sections of casings which fasten to form a sealed casing joint capable of withstanding 52 us. (:1. 166/207 pressure and formation loads as the casing is expanded [5 1] Int. Cl E21b 43/10 and locked into Position The expandable easing elabll' 58 Field 6: Search 166/207 izes wellbores, Preventing deformation, fracturing or fluid communication between fluids conducted within 5 References Ci d the wellbore and formations isolated through use of the UNITED STATES PATENTS casing. The casing sections are attached to an inflatable 2 583 316 1 1952 B 166 207 bladder element which affords placement through 2812025 1111957 zg g 1664207 smaller diameter wellbores and orderly expansion of 18802l8 10/1932 sirmgnons 166,207 the sections in the wellbore adjacent to the formation 3,134,442 5 1964 Jennings 166 207 be stablllzed Protected- 3,364,993 1/1968 Skipper 166/207 3,412,565 11/1968 Lindsey et al. 166/207 7 Clam, 3 9mm"! Patented Jul 17, 1973 3,746,092

2 Sheets-Sheet 1 FIG. 2

KARL M. LAND, INVENTOR.

ATTORNEY.

Patented July 17, 1973 3,746,092

2 Sheets-Sheet 2 KARL M. LAND INVENTOR.

ATTORNEY.

MEANS FOR STABILIZING WELLBORES BACKGROUND OF THE INVENTION This invention relates to means for stabilizing a wellbore. More particularly, the present invention represents apparatus comprising expandable casing, the use of which prevents deformation, fracturing and fluid communication between fluids transported within a wellbore and formation fluids.

Wellbore deformation and instability, for example that caused by salt flow, sloughing of shale deposits, low mud circulation, etc., resulting within fractured or highly porous formations are frequent problems associated with drilling and completion of hydrocarbon and mineral bearing formations. In the completion or production of hydrocarbons and minerals from subterranean reservoirs, often formations are encountered having lower constituency than desirable for the completion of production tubing and wellbore liners therein. Therefore, during the production interval of the hydrocarbon or mineral containing reservoir, one may encounter a failure of the wellbore completion through deformation of the wellbore liner or production equipment associated therewith, fracturing through the wellbore liner and formation, thereby causing losses of wellbore fluids or fluid communication between wellbore formations through the annulus formed between the formation and the wellbore liner giving undesirable consequences to the production operation.

Conventional methods and apparatus available for combating wellbore deformation, fracturing or fluid communication comprise complicated wellbore apparatus for the removal of wellbore liners and the replacement thereof or for the recementing and setting of wellbore equipment therein. The inherent problem in all conventional wellbore stabilization equipment for the continued and enhanced production of fluids therefrom subsequent to deformation, fracturing or fluid communication of wellbore fluids with the formations are associated with unreliable solutions which are expensive, time consuming and often have dangers associated therewith. What is required is a reliable technique whereby wellbore deformation and stability may be controlled so as to prevent lost circulation resulting from fractured or highly porous formations being encountered during drilling, completion or production of a wellbore to prevent wellbore deformation and fluid communication from occurring.

It is an object of the present invention to provide apparatus for the stabilization of wellbores.

It is another object of the present invention to provide apparatus for the protection of tubular goods and the cement sheath within a completed wellbore.

It is still a further object of the present invention to provide apparatus whereby the tubular goods contained within a completed well-bore may be stabilized or further reinforced through introduction of the apparatus of the present invention.

With these and other objects in mind, the present invention is hereinafter set forth with particular reference to the following drawings and description:

SUMMARY OF THE INVENTION The objects of the present invention are accomplished through utilization of apparatus for the stabilization of a wellbore to prevent deformation, fracturing or fluid communication between the wellbore and surroundig formations. The apparatus comprises at lesat two inside axial casing sections circularly aligned with at least two outside axial casing sections circularly aligned about the inside axial casing sections. An inflatable bladder section is provided to connect the inside and outside axial casing sections so that they are normally aligned, with the inside axial casing sections contained within the outside axial casing sections but capable of being positioned so as to form a circular casing joint through inflation of the inflatable bladder section. Means for inflating the inflatable bladder section are provided so that a circular casing joint may be formed from the axial casing sections. It is preferred that the means for inflating the inflatable bladder section be hydraulic.

It is generally preferred that the apparatus of the present invention further comprise the inside axial casing sections having locking serrations on the exterior portion and that the outside axial casing sections further comprise locking serrations on the interior portions which meet with the locking serrations of the inside axial casing sections to lock the axial casing sections into the form of a circular casing joint. In conjunction with the locking serration sections, the apparatus further comprises means for sealing the joints formed between the inside and outside axial casing sections when they are connected to form a circular casing joint.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be more fully understood through referral to the accompanying FIGS. in which:

FIG. 1 represents a set of three inside axial casing sections and three outside axial casing sections in a collapsed position forming one embodiment of the apparatus of the present invention;

FIG. 2 depicts the inside and outside axial sections of FIG. 1 in an expanded and locked position; and

FIG. 3 depicts the apparatus of the present invention further comprising a preferred embodiment utilizing a placement tool in which the inside and outside axial casing sections may be deflated in conjunction with an inflatable bladder in order to prevent deformation, fracturing or fluid communication in the wellbore.

DETAILED DESCRIPTION OF THE INVENTION The present invention discloses apparatus for the stabilization of wellbores so as to prevent deformation, fracturing, fluid communication and other undesirable physical phenomenas from occuring within the wellbore. The embodiment of the present invention-is most easily understood by referral to FIG. 1 in which three inside axial casing sections 10!, being circularly aligned, are depicted in conjunction with three outside axial casing sections 102 circularly aligned about the inside axial casing sections 101. An inflatable bladder section 106 connects the inside and outside axial casing sections 101 and 102, respectively, so as to place the inside axial casing sections 101 within the outside axial casing sections 102, but capable of being positioned so as to form a circular casing joint through inflation of the inflatable bladder section 106. The apparatus of the present invention is depicted in FIG. 1 and comprises inside axial casing section 101 comprising locking serrations 104 on the exterior portion thereof with the outside axial casing sections including locking serrations 103 on the interior portion thereof to mate with and outside axial casing sections 202 in expanded and locked position wherein the inflatable bladder section 206 has been expanded so as to force the axial casing sections to connect to form a circular casing joint. The locking serrations 203 and 204, respectively, contained upon the inside axial casing sections 201 and outside casing sections 202 mate and lock the axial casing sections to form a circular casing joint. Means for sealing the joints formed between the inside and butside axial casings sections 201 and 202, respectively, may comprise, as shown, the rubber seals 20S, positioned such that no fluid communication may occur between the interior and exterior of the circular casing joint formed.

Therefore, in the normal operation within a wellbore, the expandable casing joints formed by the apparatus of the present invention may be attached to an inflatable bladder element. The apparatus allows for placement of the casing joint through smaller diameter wellbores and orderly expansion of the axial casing sections within enlarged or underreamed portions of a wellbore adjacent to the zone or formation to be stabilized. The expandable casing apparatus of the present invention may be utilized within encased or cemented wellbores for the repair thereof, or may be utilized in an open hole wherein degradation of the formation and hole enlargement is incurred in which oversized casing joint is required in order to give an adequate completion through further cementing.

One embodiment of the apparatus for positioning the expandable casing joints of the present invention is depicted in FIG. 3. Illustrated is a tool for running the expandable casing apparatus of the present invention. In the Figure, the expanded casing 312 is depicted, connected to a standard joint of drill pipe 319 through connection of threadable section 314 to a drill string 315. In the Figure, a drilled hole 311 is shown in which overreaming has occurred due to collapse of a formation 310 such that expanded casing is required for an adequate cementing job or completion to be accomplished. The axial casing sections are expanded within the overreamed area, as shown in the Figure, through the utilization of the pipe 319. The pipe 319 has a deflation port 316 and inflation port 317 containing a check valve 318 therein for the introduction and withdrawal from the annular section 320 formed between the expanding casing 312 and pipe 319. Deflation port 316 is normally blocked from fluid flow from within the pipe 319 by a first sliding sleeve valve 324 which is activated by the introduction ofa valve ball 326. When activated, the sliding sleeve valve moves vertically downward inside the pipe 319 until it abutts with recess 334, thereby exposing deflation port 316 to the interior of the pipe 319. In a similar fashion, a second sliding sleeve valve 322 blocks fluid flow-through inflation port 317, but may be activated by introduction of sleeve ball 323 which slideably moves the sliding sleeve valve 322 downwardly within the pipe 319' until it abutts with reamed surface 321, so as to expose the inflation port 317 to fluid flow. The inflation port 317 contains a check valve 318 which prevents fluid egress from the annulus 320 after the expanded casing 312 is positioned. Means are provided for controlling flow of fluids through the inflation or deflation ports through the sliding sleeves. Also, means are provided for preventing the flow of fluid through the pipe while the bladder section is being inflated through the use of the sliding sleeves.

In conjunction with the apparatus depicted in the FIG. 3 are means for preventing flow of fluids through the pipe comprising a first bypass port 327 contained within the pipe wall 319 having an inlet 330 at or'below the inflation port 317 and an exit 331 below the secondslideable sleeve 322 positioned so that fluid flow through the inlet 330 is normally blocked when the second sliding valve 322 is activated by valve ball 323. A bypass check valve 328 is located within the first bypass port 327 so as to prevent reverse flow of fluids from the exit 331 to the inlet 332. Means for normally preventing flow through the first bypass port 327 when it is exposed through the activation of the second sliding sleeve valve 322 are provided which may comprise a pressure burst plate 329 located within the first bypass port 327 which will burst when a predetermined pressure buildup is exhibited within the pipe 319. The apparatus may further comprise a second bypass port 325 having an inlet 333 at or above the deflation port 316 and exit 332 into the first bypass port 327 below the first sliding sleeve valve 324 positioned so that fluid flow through the inlet 333 is normally opened when the first sliding valve 324 is activated.

In the utilization of the apparatus of the present invention, the following procedure may be utilized for running a length of expandable casing in an uncompleted hole:

l. Underreaming the zone where casing is to be set;

2. Running expandable casing on a bladder with the drill pipe open for circulation;

3. When the expandable casing is at the proper depth, a small diameter sleeve valve plug (ball) is dropped, causing a sliding sleeve valve to be actuated opening inflation ports into the bladder and closing circulation into the annulus, the bladder is thus expanded using drill pipe or tubing pressure;

4. After expansion, the pump pressure is increased slightly to rupture the burst plates and allow annulus circulation;

5. Cement is then circulated behind the expanded casing and overflushed to clear the running tool;

6. A second valve plug is dropped to actuate a sliding sleeve valve and open deflation ports and annulus ports; and

7. The running tool is retrieved to surface after defla tion. Therefore, through utilization of the apparatus of the present invention, one is afforded the means and method for stabilizing the wellbore for the prevention of deformation, fracturing or fluid communication so that loss of circulation due to salt flow, sloughing of shales, loss of hole or collapse of pipe, etc., may be circumvented through the optimal production and completion of a wellbore.

While the invention has been described herein with respect to certain embodiments thereof, it will be understood by those skilled in the art that various changes Therefore, I claim: 1. An apparatus for the stabilization of a wellbore for the prevention of deformation, fracturing, fluid communication, etc., which comprises:

a. at least two inside axial casing sections circularly aligned and including locking serrations on the exterior portion thereof;

b. at least two outside axial casing sections circularly aligned about the inside axial casing sections and including locking serrations on the interior portion thereof which mesh with the locking serrations of the inside axial casing sections to lock the axial casing sections into the form of a circular casing joint;

c. an inflatable bladder section connecting the inside and outside axial casing sections so that the inside axial casing sections are contained within the outside axial casing sections but capable of being positioned so as to form said circular casing joint through inflation of the inflatable bladder section:

d. hydraulic means for inflating the inflatable bladder section;

e. means for locking the axial casing sections when expanded; and

f. means for sealing the joints formed between the inside and outside axial casing sections when they are connected to form said circular casing joint.

2. The apparatus of claim 1 wherein the hydraulic means for inflating the inflatable bladder section comprise:

controlling the flow of fluids through the inflation or deflation ports comprise:

a. an inflation check valve positioned within each of the inflation ports so as to prevent the egress of fluids from within the annulus to within the pipe;

b. a first sliding sleeve valve positioned to normally block the flow through the one or more deflation ports; and

c. means for activating the first sliding sleeve valve.

4. The apparatus of claim 3 further comprising:

a. a second sliding sleeve valve positioned to normally block the flow through the one or more inflation ports; and

b. means for activating the second sliding sleeve valve.

5. The apparatus of claim4 further comprising:

a. the first and second sliding sleeve valve being ball activated with the means for preventing the flow of fluid through the pipe comprising a first bypass port contained within the pipe wall having an inlet at or above the inflation port and an exit below the second sliding sleeve valve positioned so that fluid flow through the inlet is normally blocked but allowed when the second sliding valve is activated;

b. a bypass check valve located within the first bypass port so as to prevent reverse flow of fluids from the exit to the inlet; and

0. means for normally preventing flow through the first bypass port when it is exposed through activation of the second sliding sleeve valve.

6. The apparatus of claim 5 in which the means for normally preventing flow through the first bypass port comprise a pressure burst plate located within the first bypass port which will burst when a predetermined pressure buildup is exhibited within the pipe.

7. The apparatus of claim 6 further comprising a second bypass port having an inlet at or above the defiation port and an exit into the first bypass port below the first sliding sleeve valve positioned so that fluid flow through the inlet is normally blocked, but allowed when the first sliding valve is activated. 

1. An apparatus for the stabilization of a wellbore for the prevention of deformation, fracturing, fluid communication, etc., which comprises: a. at least two inside axial casing sections circularly aligned and including locking serrations on the exterior portion thereof; b. at least two outside axial casing sections circularly aligned about the inside axial casing sections and including locking serrations on the interior portion thereof which mesh with the locking serrations of the inside axial casing sections to lock the axial casing sections into the form of a circular casing joint; c. an inflatable bladder section connecting the inside and outside axial casing sections so that the inside axial casing sections are contained within the outside axial casing sections but capable of being positioned so as to form said circular casing joint through inflation of the inflatable bladder section: d. hydraulic means for inflating the inflatable bladder section; e. means for lockiNg the axial casing sections when expanded; and f. means for sealing the joints formed between the inside and outside axial casing sections when they are connected to form said circular casing joint.
 2. The apparatus of claim 1 wherein the hydraulic means for inflating the inflatable bladder section comprise: a. a section of pipe passing therethrough the circularly aligned axial casing sections and attached thereto the inflatable bladder section so as to form an annulus therebetween the exterior of the pipe and the interior of the circularly aligned axial casing sections, and having one or more deflation and inflation ports located therein the pipe; and b. means for controlling the flow of fluids through the inflation or deflation ports.
 3. The apparatus of claim 2 wherein the means for controlling the flow of fluids through the inflation or deflation ports comprise: a. an inflation check valve positioned within each of the inflation ports so as to prevent the egress of fluids from within the annulus to within the pipe; b. a first sliding sleeve valve positioned to normally block the flow through the one or more deflation ports; and c. means for activating the first sliding sleeve valve.
 4. The apparatus of claim 3 further comprising: a. a second sliding sleeve valve positioned to normally block the flow through the one or more inflation ports; and b. means for activating the second sliding sleeve valve.
 5. The apparatus of claim 4 further comprising: a. the first and second sliding sleeve valve being ball activated with the means for preventing the flow of fluid through the pipe comprising a first bypass port contained within the pipe wall having an inlet at or above the inflation port and an exit below the second sliding sleeve valve positioned so that fluid flow through the inlet is normally blocked but allowed when the second sliding valve is activated; b. a bypass check valve located within the first bypass port so as to prevent reverse flow of fluids from the exit to the inlet; and c. means for normally preventing flow through the first bypass port when it is exposed through activation of the second sliding sleeve valve.
 6. The apparatus of claim 5 in which the means for normally preventing flow through the first bypass port comprise a pressure burst plate located within the first bypass port which will burst when a predetermined pressure buildup is exhibited within the pipe.
 7. The apparatus of claim 6 further comprising a second bypass port having an inlet at or above the deflation port and an exit into the first bypass port below the first sliding sleeve valve positioned so that fluid flow through the inlet is normally blocked, but allowed when the first sliding valve is activated. 